Cooling a captive 4 stroke

Author

Message

David Grantham

Location : Midlands, England

Subject: Cooling a captive 4 stroke Sun Oct 26, 2014 9:33 am

I need to cool my 4 stroke live diesel project. I have a miniature ducted fan aircraft engine which is about 35mm in diameter and probably ideal for the job in hand. Clearly it needs something between it and a dc battery to switch polarity ie act as a commutator does in a BDC motor.

Is this something a BLDC ESC does and will it power up to full speed when connected to a battery if I do not have the ESC connected to a radio receiver.

I just want to run the ducted fan without any radio control input.

Apologies to any experts if the answer is obvious and thanks in anticipation.

Last edited by David Grantham on Tue Oct 28, 2014 9:06 am; edited 1 time in total

Bearcastle

Location : Brie

Subject: Re: Cooling a captive 4 stroke Sun Oct 26, 2014 7:04 pm

Where is coming the power from :Battery or the generator ?

What voltage need your fan ?

David Grantham

Location : Midlands, England

Subject: Re: Cooling a captive 4 stroke Sun Oct 26, 2014 9:04 pm

Power for the fan will come from a LiPo or MiH battery at between 7 and 12 volts.

Bearcastle

Location : Brie

Subject: Re: Cooling a captive 4 stroke Mon Oct 27, 2014 11:07 am

And for the fan what is the voltage ?

David Grantham

Location : Midlands, England

Subject: Re: Cooling a captive 4 stroke Mon Oct 27, 2014 4:09 pm

Anything between 7 and 12 volts

Saint-Oblas

Location : Lyon, France

Subject: Re: Cooling a captive 4 stroke Tue Oct 28, 2014 8:58 am

I have the same concern. I am afraid that the original motor will pull too much power; maybe running it at minimum speed would be OK though. Maybe replacing it with a standard DC motor running at lower speeds (thus giving lesser flox rate and pulling lesser power) would be a solution.

Bearcastle

Location : Brie

Subject: Re: Cooling a captive 4 stroke Thu Oct 30, 2014 1:44 pm

There's several possibilities.

1 - Direct But always on, and draining the battery so as you say not the best option.

2 - You could use a dedicated circuitery like this one

http://www.electroschematics.com/4935/pc-fan-controller/

Its a DC fan control circuit, by changing some resistor you could make it start at a higher degree Celsius There's a lot of circuit on the net, this one looks simple.

3 - You could use an Aduino micro controller. And it could do more than controlling the temperature and the fan, you could add other possibilities, like blinking LED and control some servo motor. Everything is in the programming, but you could have some help from the community and learn it, its a derivative from the C language.

Here an example, you don't have to use a module to visalize what's it is doing because when embedded onboard, it will do it automatically and some Arduino are very small. http://www.electroschematics.com/9540/arduino-fan-speed-controlled-temperature/

Those site will give you an idea of what is possible, but the community on the net is huge. http://arduino.cc/ http://www.adafruit.com/ https://www.sparkfun.com/

There's a lot of project that you could copy. Here some forum. http://forum.arduino.cc/ https://forums.adafruit.com/ http://www.instructables.com/tag/type-id/category-technology/channel-arduino/

There's a ot of small module ready to be use at very interresting price. The original site and other are quite expensive but this one is doing copy at a very cheap price. I ordered already from them, took some time (more than a month sometimes, but always have it delivered). http://www.banggood.com/Wholesale-Arduino-SCM-and-3D-Printer-Acc-c-2153.html

I have one already with few module, in order to know how to use it because for our hobby it open a lot of possibilities. I plan to use a very small arduino called a nano, so I could have it on board the locomotive.

There's several type of Arduino, they are mainly the same, just the size and capability change, here a picture of the nano. http://dangerousprototypes.com/forum/viewtopic.php?t=724

David Grantham

Location : Midlands, England

Subject: Re: Cooling a captive 4 stroke Thu Oct 30, 2014 8:46 pm

Thank you very much Bearcastle for your substantial and comprehensive reply. It will take me some time to understand the detail.

In the meantime after about 3 elapsed years of trying I maybe have something that would work in a live diesel loco after failing with direct drives, universal drives, metal gears and reinforced ribbed belts, all of which rapidly disintegrated in proportion to my interest.

http://www.youtube.com/watch?v=IKJpCuzkCO4

Doesn't sound much like a Napier 18 cylinder Deltic but not bad.Grateful acknowledgement to Carl Hibbs and Ken Toone for their unfailing support.

Bearcastle

Location : Brie

Subject: Re: Cooling a captive 4 stroke Thu Oct 30, 2014 9:05 pm

Nice I should do the same, but not yet done it.(Got all the equipement on a shelf...)

What is a spigot drive ?

dewintondave

Location : New Zealand

Subject: Re: Cooling a captive 4 stroke Fri Oct 31, 2014 1:22 am

Hi David. Miniature cooling fans 30 mm & 40 mm dia are available and draw low current, 5 V or 12 V. They may be more economical on power. Once the engine is up to temperature the fan could be manually switched on.

The beauty of alcohol as a fuel is that it has great cooling ability. Increasing the richness of the needle setting brings down the cylinder head temperature, and the extra oil helps. Castor oil provides most protection against seizing in. This all makes for lots of nice smelling smoke in the garden. My engine is run at idling speed and wouldn't be making as much power as a faster application.

Best wishes,Dave.

Bearcastle

Location : Brie

Subject: Re: Cooling a captive 4 stroke Fri Oct 31, 2014 3:30 pm

I've found something interesting for 6,44 $ free delivery (france), probably the same for you, on the bangood shop.

I think the fan I have may have perfect attributes but it has 3 input wires and my battery has only 2 terminals. What do I fit between these two items to make the fan turn. If the answer is an Electronic Speed Controller for a Brushless DC fan do I have to make an input into the ESC from the radio receiver to make the fan turn, because all I really want is a fixed speed fan.

Dave, do you make your own fuel. The mix I have been using is 10% Nitro 15% Synthetic Oil and 3% Castor. Is your recipe sans Nitromethane ?

Bearcastle

Location : Brie

Subject: Re: Cooling a captive 4 stroke Sat Nov 01, 2014 7:05 pm

Have you got some pictures of it, and some reference on it ?

dewintondave

Location : New Zealand

Subject: Re: Cooling a captive 4 stroke Mon Nov 03, 2014 5:56 am

David Grantham wrote:

Thanks Bearcastle and Dave for your replies.

---

Dave, do you make your own fuel. The mix I have been using is 10% Nitro 15% Synthetic Oil and 3% Castor. Is your recipe sans Nitromethane ?

David, for your fan, if it's the same type as for a PC fan.The black cable sould be the negative, red the positive and yellow or green are for the tacho.

Saint-Oblas

Location : Lyon, France

Subject: Re: Cooling a captive 4 stroke Tue Nov 04, 2014 3:50 pm

Bearcstle,

I am not sure the fan David is speaking of is the same type as a PC fan. Even if PC fans use brushless DC motor, they own a specific (low power) device to drive their BLDC. The fan David relates to, I assume, is a small turbine type with a relatively high power (considering the size) BLDC which needs an external ESC. I have not found simple electronic device that can draw a BLDC; the less sophisticated system would be a small ESC with a device as a servo tester to drive it such as:

http://www.sussex-model-centre.co.uk/shopexd.asp?id=35750

but there are many others.

Bearcastle

Location : Brie

Subject: Re: Cooling a captive 4 stroke Tue Nov 04, 2014 7:15 pm

It's a servo tester, not sure you can test a fan with it !

Saint-Oblas

Location : Lyon, France

Subject: Re: Cooling a captive 4 stroke Wed Nov 05, 2014 6:33 am

Sure it is! I did not mean testing the fan, but giving the set point to the ESC feeding the fan (of course if you have a free chanel on your RC you dod not need it). This allows controlling the fan without any RC. All what youy need is a small ESC with BEC: the ESC is connecetd to the battery by the main DC lines, to the fan by main three triphase lines and to the tester by the RC line as below:

David Grantham

Location : Midlands, England

Subject: Re: Cooling a captive 4 stroke Thu Nov 06, 2014 11:40 am

S-O brilliant, that is exactly what I need. Very many thanks to both yourself and Bc for explaining this for me.

Saint-Oblas

Location : Lyon, France

Subject: Re: Cooling a captive 4 stroke Fri Nov 07, 2014 6:54 am

There may be a draw-back: starting the device. I am not sure that after a shutdown, il will boot correctly if left in the working position: this may depend of the brand of the tester. (and the ESC?). You may have to go to the zero point when starting.

David Grantham

Location : Midlands, England

Subject: Re: Cooling a captive 4 stroke Fri Nov 07, 2014 9:24 am

S-O, thanks for the warning. I have ordered the parts I need and these are sufficiently inexpensive for experimentation to be feasible. I will let you know how I progress.